The whole nation was caught off guard when those planes were hijacked and turned into missiles 10 years ago on Sept. 11, 2001. In the wake of the tragedy, Congress greatly expanded the power of the executive branch, allowing officials to track phone calls without warrants and to hold suspects who weren't charged with crimes.
Rep. Gerry Connolly (D-Va.) says there's a fine line that should never be crossed in the name of security.
"We can't rationalize the erosion of our own civil liberties for the sake of our civil liberties," he says. "I believe that national security is not and must not be incompatible with the American character which prizes civil liberties above everything else, so we have to make the two compatible and I believe we can."
After the attacks, D.C. also got a face lift, with new security barriers and some bomb shields attached to federal buildings. But Democratic Rep. Jim Moran (Va.) says U.S. security forces need to continue their transformation along with Al Qaeda and foreign governments.
"I don't think that the kind of terrorist attacks that we experienced ten years ago are as much of a threat today as a serious cyber attack," says Moran.
Officials say future cyber attacks could cripple the U-S economy if they aren't repelled.